This project seeks to understand the phenotypic development of early stimulus preferences in Japanese quail chicks, as an experimental model system in which to investigate the genetic and environmental determination and neural representation of preference information. Seven quail populations that exhibit genetically distinct unconditional approach preferences between, and imprintabilities to, simple visual stimuli are studied. Experimentation includes (1) continued artificial selection and quantitative genetic analysis of unconditional stimulus preferences, (2) similar selection and analysis of "Hi" and "Lo" environmental imprintabilities of particular preferences, (3) establishment of behavioral baselines for neurobiological comparison of the mediation of manifestly identical but in developmental terms different, genetically determined and acquired preference information, and (4) search for the separate and interactive neural representation of gene effects and environmental influences in preference information. The anticipated data and conceptual modeling are relevant to the understanding of diathesis - environment interaction in behavioral deviations, including human behavioral pathology, and should generate new knowledge about the ways the vertebrate brain encodes and processes genetically and environmentally variable stimulus information.